Ray Stanford says:
Neither of the "Confuciusornis sanctus" specimens on display show
the DIAGNOSTIC PNEUMATIC FORAMEN! Yes, the humerous is expanded
proximally, but no such pneumatic foramen is to be seen! Could we
actually have a different species there? Or, could it be that the
pneumatic foramen only exists in the species for a certain age span and the
diagnosis needs to be altered?
My reply: We will almost certainly hear more about this at SVP. Some bird
experts (Chiappe and others) are hard at work making sense of these
critters.
--John R. Hutchinson